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Dyck, Jeffrey S.; Hajek, P.; Lošťák, P.; Uher, Ctirad

doi:10.1103/physrevb.65.115212

Cited by 137 publications

(121 citation statements)

References 27 publications

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“…The Fermi level is thereby shifted to the valence band (Fig. 2b), which is consistent with previous experimental findings [33]. V doping also decreases the bulk gap from 123 meV to 76 meV at the 2.08% V concentration, which originates from the V contribution to the valence band maximum (VBM) (Fig.…”

supporting

confidence: 79%

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High-Temperature Quantum Anomalous Hall Effect inn−pCodoped Topological Insulators

Qiao

Deng

et al. 2016

Phys. Rev. Lett.

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The quantum anomalous Hall effect (QAHE) is a fundamental quantum transport phenomenon that manifests as a quantized transverse conductance in response to a longitudinally applied electric field in the absence of an external magnetic field, and promises to have immense application potentials in future dissipation-less quantum electronics. Here we present a novel kinetic pathway to realize the QAHE at high temperatures by n-p codoping of three-dimensional topological insulators. We provide proof-of-principle numerical demonstration of this approach using vanadium-iodine (V-I) codoped Sb2Te3 and demonstrate that, strikingly, even at low concentrations of ∼2% V and ∼1% I, the system exhibits a quantized Hall conductance, the tell-tale hallmark of QAHE, at temperatures of at least ∼ 50 Kelvin, which is three orders of magnitude higher than the typical temperatures at which it has been realized so far. The proposed approach is conceptually general and may shed new light in experimental realization of high-temperature QAHE. Two-dimensional electron systems (2DESs) are versatile playgrounds for complex quantum transport phenomena that are of interest both from fundamental and application points of view. One prominent example is the quantum Hall effect (QHE) [1, 2], a quantum analogue of the classical Hall effect, whereby the application of a magnetic field to a 2DES results in the quantization of the transverse conductance and a vanishing longitudinal conductance. Crucially, the mechanisms underlying this phenomenon are the formation of an insulating bulk and remarkable chiral conducting edge states (Fig. 1a). This striking unidirectionality makes backscattering impossible, and renders transport along these edge states remarkably robust against any impurities [3,4]. This robustness essentially renders the edges of 2DESs manifesting the QHE as perfectly conducting one-dimensional (1D) wires, which would be of great interest as potential building blocks, such as interconnects between chips, in dissipation-less electronics. However, a major constraint for practical use of this fundamental quantum transport phenomenon is the requirement of very strong magnetic fields, which is impractical for realistic applications.Realizing the quantum anomalous Hall effect (QAHE) would circumvent this problem because it manifests the same hallmark features as the QHE, but does not require the application of an external magnetic field [5]. The reason why the QAHE does not require the application of an external field is because the latter's role is played by an intricate cooperation between the intrinsic magnetism that breaks the time-reversal symmetry and spin-orbit coupling in the 2D (quasi-2D) insulating host material. Initial proposals for realizing the QAHE were based on honeycomb lattice models [5]. Since then, especially after the experimental discoveries of graphene (with an inherent honeycomb lattice structure) [6] and topological insulators (TIs) [7,8], much effort has been made to exploring new platforms for realizing QAHE in th...

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supporting

confidence: 79%

“…To elucidate the role of codoping in realizing hightemperature QAHE, we first investigate the energetics and magnetic behavior of Sb 2 Te 3 solely doped with V, whereby V dopants substitute Sb atoms [33]. The interaction energy between two V atoms is defined as…”

mentioning

confidence: 99%

High-Temperature Quantum Anomalous Hall Effect inn−pCodoped Topological Insulators

Qiao

Deng

et al. 2016

Phys. Rev. Lett.

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“…Experimentally very similar to the idea of diluted magnetic semiconductors, by doping substitutionally transition metals into conventional semiconductors (Ge [62], GaAs [63], ZnO [64], etc. ), ferromagnetic ordering was achieved in the transition-metaldoped TIs [65][66][67]. The opening of the surface band was shown first for Fe-and Mn-doped Bi 2 Se 3 bulk samples, grown by a Bridgman growth method [61].…”

Section: Transition-metal Doping For Ferromagnetismmentioning

confidence: 99%

Review of 3D topological insulator thin‐film growth by molecular beam epitaxy and potential applications

Kou

Wang

2013

Physica Rapid Research Ltrs

151

152

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Abstractmagnified imageThin films of V–VI compound semiconductors (Bi2Se3, Bi2Te3 and Sb2Te3) have been synthesized recently as three‐dimensional topological insulators (TIs). Although these materials have been used as thermoelectric materials for many years, for future studies and applications of the topological surface states, a major bottleneck remains the lack of high‐quality bulk materials that have very few defects and the Fermi level can be moved to inside the bulk bandgap. In this paper, we review the use of molecular beam epitaxy (MBE) technique to achieve high‐quality TI materials. Furthermore, the use of layered growth in MBE affords us the fabrication of heterostructures, such as quantum wells and superlattices. Thus, it may further enable additional studies and applications, similar to those of conventional semiconductor heterostructures but with the novel properties of TI. We explore the growth mechanism, providing a detail discussion on the growth parameters of thin‐film synthesis by MBE. Then we discuss more complex cases, such as functional doping, heterostructures and superlattices. Potential new properties in such quantum structures are discussed. Finally, we give an outlook on this material system for both fundamental studies and applications. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…Doping magnetic elements into TI may induce ferromagnetism that breaks time reversal symmetry, resulting in these exotic phenomena. Ferromagnetic behaviors have been observed in various magnetic TIs, such as Mn doped Bi 2 Te 3 , 9 Cr and V doped Sb 2 Te 3 , [10][11][12] and Cr doped Bi 2 Se 3 . 13 Finally, QAHE was experimentally confirmed in Cr doped Bi x Sb 2−x Te 3 thin films, which completes the quantum hall effect trio.…”

mentioning

confidence: 99%

Visualizing ferromagnetic domains in magnetic topological insulators

Wang

Gao

et al. 2015

APL Materials

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We report a systematic study of ferromagnetic domains in both single-crystal and thin-film specimens of magnetic topological insulators Cr doped (Bi0.1Sb0.9)2Te3 using magnetic force microscopy (MFM). The temperature and field dependences of MFM and in situ resistance data are consistent with previous bulk transport and magnetic characterization. Bubble-like ferromagnetic domains were observed in both single crystals and thin films. Significantly, smaller domain size (∼500 nm) with narrower domain wall (∼150 − 300 nm) was observed in thin films of magnetic topological insulators, likely due to vertical confinement effect. These results suggest that thin films are more promising for visualization of chiral edge states.

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Diluted magnetic semiconductors based onSb2−xVxTe

Cited by 137 publications

References 27 publications

High-Temperature Quantum Anomalous Hall Effect inn−pCodoped Topological Insulators

High-Temperature Quantum Anomalous Hall Effect inn−pCodoped Topological Insulators

Review of 3D topological insulator thin‐film growth by molecular beam epitaxy and potential applications

Visualizing ferromagnetic domains in magnetic topological insulators

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